Travel from Florence to Sorrento

I think the bus may leave only from the airport, but we took the Circumvesuvina just to have the experience. I doubt it is as hot or crowded now as it was during the height of the summer travel season. An obvious solution for all but the lowest budget travelers is to have your hotel recommend a land-travel partner car service, probably about 100 Euros one way, from the Naples rail station to the hotel door. You'd pay at least 15 Euros for a taxi from the Circumvesuviana station to the CLOSEST hotel. If your hotel is on the edge of town, a car service becomes a compelling option.

I hope you bought your train tickets Florence-Naples early enough to get the massive (non-changeable, non-refundable) discount for two or three months in advance.

The only reason the Circumvesuviana is hard to do with luggage is the crowding on the train. It's like London Underground at the height of rush hour, let's say. One of you will have to stand and watch the bags, IF there is a seat for the other. The Naples and Sorrento stations have elevators, of course heavily used. If you told us where you live in your visible profile, we would know if you might have ever taken a city subway or commuter rail before.

You could take the Campania express since it comes with a seat reservation
http://ots.eavsrl.it/web/public/ots/ticket/index?changeLang=en

The Express is an option but it only has 4 runs per day. Unless the timing between trains works, I'd take the Circumvesuviana versus kill a lot of time waiting for the next Express.

Express schedule:
https://www.sorrentoinsider.com/en/campania-express-train-schedule

Circumvesuviana schedule:
https://www.sorrentoinsider.com/en/naples-to-sorrento-train-schedule

Another option would be to take a cab to the port in Naples and then a ferry to Sorrento. This involves more transfers than the Circ. as the port in Sorrento is below the main part of town and can require a cab or bus to reach, depending on amount of luggage. Then again, a cab or bus may also be necessary from the train to hotel depending on luggage and distance from the station.

https://www.sorrentoinsider.com/en/ferry-schedule?from=napoli&to=sorrento#

As the train station for the Circ. in Naples (Garibaldi) is connected to Napoli Centrale, it's a pretty convenient option, especially if your hotel in Sorrento is walking distance from the station there.

I would take the Trenitalia fast train to Salerno, not Naples and then take the bus with a stop in Amalfi ( bus ticket valid for 24 hours) or train to Sorrento or the boat ( nice option but available only from 1 May to 31 October).

http://www.bouganvillesalerno.it/arrivare-sorrento-salerno/

Regarding info in the link provided in the post before this one, taking a train Florence>Salerno>Sorrento means backtracking to Naples from Salerno and changing to the Circumvesuviana there - 2 train changes: Salerno and Naples - which isn't of any advantage, IMHO. You can do it with just a single change if going directly to Naples.

There are no direct ferries running from Salerno to Sorrento at this time so again, if wishing to go by sea, you'll want to do that from Naples to avoid multiple changes.

Also, the Salerno-Sorrento bus doesn't just stop in Amalfi, you have to change physical busses in Amalfi. These busses have a publshed schedule, but it is very, very long trip. I've never done it, but I'm sure the train from Salerno to Naples (!!!) and the Circumvesuviana add up to slightly less time than the two SITA busses. As just noted, it makes no sense to train to Salerno unless you want a ferry that runs in your travel season.

I suppose there is some chance of getting a window seat on the bus in October, but this location is busy all year long. In season, you're lucky to get ON the SITA bus at all, let alone get an aisle seat.

I advise you to think about your destination after Sorrento now, not after you make all your other plans. You cannot fly out of Rome after spending the night in Sorrento unless your flight is very late in the day, say, after 5PM.

We took the Campania express and found the timetable in the IT office. We had planned to store our luggage and get Pizza in Naples. We had about 4 hours between the time our train arrived and departure, plenty of time.
You can also hire a car service like Amalfi Coast Destination, I had friends that recently used them for this exact purpose and loved it. I Used them for an all day tour of the Amalfi Coast.

Another option is to take the Italo train/bus combination direct from Florence to Sorrento. You'll take a high-speed train to a new Naples station outside the city center (Naples Afragola) and transfer to an Italo bus for the ride to Sorrento. This way you can avoid the sometimes awkward transfer in Naples Centrale to the Campania Express or Circumvesuviana.

We had no issues taking the train from Florence to Naples, and then the Circumvesuviana to Sorrento. It is so convenient between the two trains, I don’t know what the ‘difficult to navigate’ could possibly mean. The C. Is like traveling on a subway vs Eurostar...no big deal. If each person can manage their own luggage there should be no issue. We had luggage and found seats easily.